src/main/java/net/pterodactylus/rhynodge/loader/ChainWatcher.java

   1 /*
   2  * Rhynodge - ChainWatcher.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.rhynodge.loader;
  19
  20 import java.io.File;
  21 import java.io.FilenameFilter;
  22 import java.io.IOException;
  23 import java.util.HashMap;
  24 import java.util.HashSet;
  25 import java.util.Map;
  26 import java.util.Map.Entry;
  27 import java.util.Set;
  28 import java.util.concurrent.TimeUnit;
  29
  30 import javax.inject.Inject;
  31 import javax.inject.Singleton;
  32
  33 import net.pterodactylus.rhynodge.Reaction;
  34 import net.pterodactylus.rhynodge.engine.Engine;
  35 import net.pterodactylus.rhynodge.loader.Chain.Parameter;
  36 import net.pterodactylus.rhynodge.loader.Chain.Part;
  37
  38 import org.apache.log4j.Logger;
  39
  40 import com.fasterxml.jackson.core.JsonParseException;
  41 import com.fasterxml.jackson.databind.JsonMappingException;
  42 import com.fasterxml.jackson.databind.ObjectMapper;
  43 import com.google.common.base.Predicate;
  44 import com.google.common.collect.Maps;
  45 import com.google.common.util.concurrent.AbstractExecutionThreadService;
  46 import com.google.common.util.concurrent.Uninterruptibles;
  47
  48 /**
  49  * Watches a directory for chain configuration files and loads and unloads
  50  * {@link Reaction}s from the {@link Engine}.
  51  *
  52  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  53  */
  54 @Singleton
  55 public class ChainWatcher extends AbstractExecutionThreadService {
  56
  57         /** The logger. */
  58         private static final Logger logger = Logger.getLogger(ChainWatcher.class);
  59
  60         /** The JSON object mapper. */
  61         private static final ObjectMapper objectMapper = new ObjectMapper();
  62
  63         /** The reaction loader. */
  64         private final ReactionLoader reactionLoader = new ReactionLoader();
  65
  66         /** The engine to load reactions with. */
  67         private final Engine engine;
  68
  69         /** The directory to watch for chain configuration files. */
  70         private final String directory;
  71
  72         /**
  73          * Creates a new chain watcher.
  74          *
  75          * @param engine
  76          *            The engine to load reactions with
  77          * @param directory
  78          *            The directory to watch
  79          */
  80         @Inject
  81         public ChainWatcher(Engine engine, ChainDirectory directory) {
  82                 this.engine = engine;
  83                 this.directory = directory.getDirectory();
  84         }
  85
  86         //
  87         // ABSTRACTEXECUTIONTHREADSERVICE METHODS
  88         //
  89
  90         /**
  91          * {@inheritDoc}
  92          */
  93         @Override
  94         protected void run() throws Exception {
  95
  96                 /* loaded chains. */
  97                 final Map<String, Chain> loadedChains = new HashMap<String, Chain>();
  98
  99                 while (isRunning()) {
 100
 101                         /* check if directory is there. */
 102                         File directoryFile = new File(directory);
 103                         if (!directoryFile.exists() || !directoryFile.isDirectory() || !directoryFile.canRead()) {
 104                                 Uninterruptibles.sleepUninterruptibly(1, TimeUnit.SECONDS);
 105                                 continue;
 106                         }
 107
 108                         /* list all files, scan for configuration files. */
 109                         logger.debug(String.format("Scanning %s...", directory));
 110                         File[] configurationFiles = directoryFile.listFiles(new FilenameFilter() {
 111
 112                                 @Override
 113                                 public boolean accept(File dir, String name) {
 114                                         return name.endsWith(".json");
 115                                 }
 116                         });
 117                         logger.debug(String.format("Found %d configuration file(s), parsing...", configurationFiles.length));
 118
 119                         /* now parse all XML files. */
 120                         Map<String, Chain> chains = new HashMap<String, Chain>();
 121                         for (File configurationFile : configurationFiles) {
 122
 123                                 /* parse XML file. */
 124                                 Chain chain = parseConfigurationFile(configurationFile);
 125                                 if (chain == null) {
 126                                         logger.warn(String.format("Could not parse %s.", configurationFile));
 127                                         continue;
 128                                 }
 129
 130                                 /* dump chain */
 131                                 logger.debug(String.format(" Enabled: %s", chain.enabled()));
 132
 133                                 if (chain.watcher() != null) {
 134                                         logger.debug(String.format("Reaction: %s", chain.watcher().name()));
 135                                 } else {
 136                                         logger.debug(String.format(" Query: %s", chain.query().name()));
 137                                         for (Parameter parameter : chain.query().parameters()) {
 138                                                 logger.debug(String.format("  Parameter: %s=%s", parameter.name(), parameter.value()));
 139                                         }
 140                                         for (Part filter : chain.filters()) {
 141                                                 logger.debug(String.format(" Filter: %s", filter.name()));
 142                                                 for (Parameter parameter : filter.parameters()) {
 143                                                         logger.debug(String.format("  Parameter: %s=%s", parameter.name(), parameter.value()));
 144                                                 }
 145                                         }
 146                                         logger.debug(String.format(" Trigger: %s", chain.merger().name()));
 147                                         for (Parameter parameter : chain.merger().parameters()) {
 148                                                 logger.debug(String.format("  Parameter: %s=%s", parameter.name(), parameter.value()));
 149                                         }
 150                                 }
 151                                 logger.debug(String.format(" Action: %s", chain.action().name()));
 152                                 for (Parameter parameter : chain.action().parameters()) {
 153                                         logger.debug(String.format("  Parameter: %s=%s", parameter.name(), parameter.value()));
 154                                 }
 155
 156                                 chains.put(getReactionName(configurationFile.getName()), chain);
 157                         }
 158
 159                         /* filter enabled chains. */
 160                         Map<String, Chain> enabledChains = Maps.filterEntries(chains, new Predicate<Entry<String, Chain>>() {
 161
 162                                 @Override
 163                                 public boolean apply(Entry<String, Chain> chainEntry) {
 164                                         return chainEntry.getValue().enabled();
 165                                 }
 166                         });
 167                         logger.debug(String.format("Found %d enabled Chain(s).", enabledChains.size()));
 168
 169                         /* check for removed chains. */
 170                         Set<String> chainsToRemove = new HashSet<String>();
 171                         for (Entry<String, Chain> loadedChain : loadedChains.entrySet()) {
 172
 173                                 /* skip chains that still exist. */
 174                                 if (enabledChains.containsKey(loadedChain.getKey())) {
 175                                         continue;
 176                                 }
 177
 178                                 logger.info(String.format("Removing Chain: %s", loadedChain.getKey()));
 179                                 engine.removeReaction(loadedChain.getKey());
 180                                 chainsToRemove.add(loadedChain.getKey());
 181                         }
 182
 183                         /* remove removed chains from loaded chains. */
 184                         for (String reactionName : chainsToRemove) {
 185                                 loadedChains.remove(reactionName);
 186                         }
 187
 188                         /* check for new chains. */
 189                         for (Entry<String, Chain> enabledChain : enabledChains.entrySet()) {
 190
 191                                 /* skip already loaded chains. */
 192                                 if (loadedChains.containsValue(enabledChain.getValue())) {
 193                                         continue;
 194                                 }
 195
 196                                 logger.info(String.format("Loading new Chain: %s", enabledChain.getKey()));
 197
 198                                 Reaction reaction = reactionLoader.loadReaction(enabledChain.getValue());
 199                                 engine.addReaction(enabledChain.getKey(), reaction);
 200                                 loadedChains.put(enabledChain.getKey(), enabledChain.getValue());
 201                         }
 202
 203                         /* wait before checking again. */
 204                         Uninterruptibles.sleepUninterruptibly(5, TimeUnit.SECONDS);
 205                 }
 206         }
 207
 208         //
 209         // STATIC METHODS
 210         //
 211
 212         /**
 213          * Parses the given configuration file into a {@link Chain}.
 214          *
 215          * @param configurationFile
 216          *            The configuration file to parse
 217          * @return The parsed chain
 218          */
 219         private static Chain parseConfigurationFile(File configurationFile) {
 220                 try {
 221                         return objectMapper.readValue(configurationFile, Chain.class);
 222                 } catch (JsonParseException jpe1) {
 223                         logger.warn(String.format("Could not parse %s.", configurationFile), jpe1);
 224                 } catch (JsonMappingException jme1) {
 225                         logger.warn(String.format("Could not parse %s.", configurationFile), jme1);
 226                 } catch (IOException ioe1) {
 227                         logger.info(String.format("Could not read %s.", configurationFile));
 228                 }
 229                 return null;
 230         }
 231
 232         /**
 233          * Extracts the name of the reaction from the given filename.
 234          *
 235          * @param filename
 236          *            The filename to extract the reaction name from
 237          * @return The name of the reaction
 238          */
 239         private static String getReactionName(String filename) {
 240                 return (filename.lastIndexOf(".") > -1) ? filename.substring(0, filename.lastIndexOf(".")) : filename;
 241         }
 242
 243         public static class ChainDirectory {
 244
 245                 private final String directory;
 246
 247                 private ChainDirectory(String directory) {
 248                         this.directory = directory;
 249                 }
 250
 251                 public String getDirectory() {
 252                         return directory;
 253                 }
 254
 255                 public static ChainDirectory of(String directory) {
 256                         return new ChainDirectory(directory);
 257                 }
 258
 259         }
 260
 261 }